I'm planning on having players be able to group up. There is the RPG chat, which allows you to create your own room (or of course, players can communicate via messenger, etc).

With the game being basically turn based, I haven't figured a way of automatically following a leader, I was thinking more of just having a group of people explore an area together while acting independently. (Wizard teleports the group out there, fighter kills some stuff, theif opens the chests, healer keeps everyone alive, that sort of thing).

It's hard to learn a lot of skills to high level, so people working as a group would have a significant advantage. However they'd then be very specialised and might find it hard going on their own.